Effect of left atrial size on the oesophageal transit of capsules.

The oesophageal transit time of barium sulphate capsules was measured using X ray fluoroscopy in 20 patients with mitral valve disease and 12 control patients in the erect and supine positions when swallowed with both 15 ml and 60 ml of water. An erect barium swallow was performed, and from a lateral radiograph the area of indentation of the oesophagus caused by the cardiac impression was measured. Left atrial diameter was derived from M mode echocardiography. In 19 patients with mitral valve disease one or more capsules remained in the oesophagus for five minutes and disintegrated there, whereas this occurred in only six control patients. Capsule transit time was significantly slower in the study patients than in the control patients in the supine position with 15 ml water. There was a significant correlation between the area of indentation and mean capsule transit time and supine 15 ml transit time. The area of indentation closely correlated with the left atrial diameter. When capsules were delayed in the oesophagus, this occurred mainly at the level of the left atrial impression in the study patients and at the lower oesophageal sphincter in the control patients. Patients with mitral valve disease are more likely than control patients to have delayed oesophageal transit of capsules because of the anatomical deformity caused by enlargement of the left atrium.